In the landscaping business a common task is to edge around landscaping, sidewalks or driveways. This can be carried out by a machine known as an edger having a blade rotated vertically by a motor driven shaft on which it is mounted. The blade used in conventional edgers is usually rectangular bar stock that can have sharpened edges near each end. One limitation is that the rotating tip of the blade makes a thin cut into the grass having a width of the blade. This is followed with cleanup by hand to remove the grass that overhangs the cut. Each blade can have multiple sections (e.g., four perpendicular rectangular cutting sections rather than just a rectangular piece of bar stock). One problem with existing edging blades is that the soil or grass is thrown up into a safety cover over the blade, which tends to lead to clogging.
U.S. Pat. No. 6,487,840 discloses a mulching and shredding blade used on lawnmowers intended to avoid having to collect grass clippings, leaves and other debris from the lawn after mowing. The blade is generally rectangular and has teeth on opposing edges near each end that have an upward slope. The blade is rotated horizontally and designed so that the upwardly sloped teeth help create an area of low pressure for keeping the clippings and leaves up near the rotating blade. The blade has a transition section including a leading cutting edge that is offset upwardly relative to a leading cutting edge of an outboard section that is located closer to the end of the blade than the transition section.
U.S. Pat. No. 6,688,095 discloses a rectangular lawnmower blade designed for horizontal rotation having upstanding teeth on the edges of the blade near each end.
U.S. Pat. No. 6,640,449 discloses a device including a cutting blade for a trimmer rotating horizontally above the ground, including two ends that are bent toward the ground for cutting and chopping of cut material such as grass, weeds, reeds, bushes and thin trees.
U.S. Pat. No. 2,312,569 discloses a lawn edger having a circular blade with teeth that alternate around the blade in the pattern: left-side tooth, intermediate tooth and right-side tooth. Additional circular blades are also used.
U.S. Pat. No. 3,358,431 discloses a rectangular blade for a lawn edger having scoops projecting toward the same side. U.S. Pat. No. 6,464,015 discloses a lawn edger including a circular blade having ribs protruding from the same side of the blade.